S100A4 plays an important role in tumor metastasis by regulating adhesion,10 extracellular matrix remodeling,11,12 and cellular motility.13,14 S100A4 secreted from liver cancer-associated-mesenchymal stem cells results in increased HCC invasiveness via miR155-SOCS1-MMP9 axis.15 S100A4 could be upregulated in urothelial cells after bladder cancer exosomes treatment.16 And recently, S100A4 was reported to regulate pre-metastatic niche in oncogenic pancreatic exosomes.17 Here, S100A4 is linked to liver cancer.